1 //! keysinterface provides keys into rust-lightning and defines some useful enums which describe
2 //! spendable on-chain outputs which the user owns and is responsible for using just as any other
3 //! on-chain output which is theirs.
5 use bitcoin::blockdata::transaction::{Transaction, OutPoint, TxOut};
6 use bitcoin::blockdata::script::{Script, Builder};
7 use bitcoin::blockdata::opcodes;
8 use bitcoin::network::constants::Network;
9 use bitcoin::util::bip32::{ExtendedPrivKey, ExtendedPubKey, ChildNumber};
10 use bitcoin::util::bip143;
12 use bitcoin_hashes::{Hash, HashEngine};
13 use bitcoin_hashes::sha256::HashEngine as Sha256State;
14 use bitcoin_hashes::sha256::Hash as Sha256;
15 use bitcoin_hashes::sha256d::Hash as Sha256dHash;
16 use bitcoin_hashes::hash160::Hash as Hash160;
18 use secp256k1::key::{SecretKey, PublicKey};
19 use secp256k1::{Secp256k1, Signature, Signing};
23 use util::logger::Logger;
24 use util::ser::{Writeable, Writer, Readable};
27 use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment, make_funding_redeemscript, ChannelPublicKeys, LocalCommitmentTransaction};
31 use std::sync::atomic::{AtomicUsize, Ordering};
33 use ln::msgs::DecodeError;
35 /// When on-chain outputs are created by rust-lightning (which our counterparty is not able to
36 /// claim at any point in the future) an event is generated which you must track and be able to
37 /// spend on-chain. The information needed to do this is provided in this enum, including the
38 /// outpoint describing which txid and output index is available, the full output which exists at
39 /// that txid/index, and any keys or other information required to sign.
40 #[derive(Clone, PartialEq)]
41 pub enum SpendableOutputDescriptor {
42 /// An output to a script which was provided via KeysInterface, thus you should already know
43 /// how to spend it. No keys are provided as rust-lightning was never given any keys - only the
44 /// script_pubkey as it appears in the output.
45 /// These may include outputs from a transaction punishing our counterparty or claiming an HTLC
46 /// on-chain using the payment preimage or after it has timed out.
48 /// The outpoint which is spendable
50 /// The output which is referenced by the given outpoint.
53 /// An output to a P2WSH script which can be spent with a single signature after a CSV delay.
54 /// The private key which should be used to sign the transaction is provided, as well as the
55 /// full witness redeemScript which is hashed in the output script_pubkey.
56 /// The witness in the spending input should be:
57 /// <BIP 143 signature generated with the given key> <empty vector> (MINIMALIF standard rule)
58 /// <witness_script as provided>
59 /// Note that the nSequence field in the input must be set to_self_delay (which corresponds to
60 /// the transaction not being broadcastable until at least to_self_delay blocks after the input
62 /// These are generally the result of a "revocable" output to us, spendable only by us unless
63 /// it is an output from us having broadcast an old state (which should never happen).
65 /// The outpoint which is spendable
67 /// The secret key which must be used to sign the spending transaction
69 /// The witness redeemScript which is hashed to create the script_pubkey in the given output
70 witness_script: Script,
71 /// The nSequence value which must be set in the spending input to satisfy the OP_CSV in
72 /// the witness_script.
74 /// The output which is referenced by the given outpoint
77 /// An output to a P2WPKH, spendable exclusively by the given private key.
78 /// The witness in the spending input, is, thus, simply:
79 /// <BIP 143 signature generated with the given key> <public key derived from the given key>
80 /// These are generally the result of our counterparty having broadcast the current state,
81 /// allowing us to claim the non-HTLC-encumbered outputs immediately.
83 /// The outpoint which is spendable
85 /// The secret key which must be used to sign the spending transaction
87 /// The output which is reference by the given outpoint
92 impl Writeable for SpendableOutputDescriptor {
93 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
95 &SpendableOutputDescriptor::StaticOutput { ref outpoint, ref output } => {
97 outpoint.write(writer)?;
98 output.write(writer)?;
100 &SpendableOutputDescriptor::DynamicOutputP2WSH { ref outpoint, ref key, ref witness_script, ref to_self_delay, ref output } => {
102 outpoint.write(writer)?;
104 witness_script.write(writer)?;
105 to_self_delay.write(writer)?;
106 output.write(writer)?;
108 &SpendableOutputDescriptor::DynamicOutputP2WPKH { ref outpoint, ref key, ref output } => {
110 outpoint.write(writer)?;
112 output.write(writer)?;
119 impl Readable for SpendableOutputDescriptor {
120 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
121 match Readable::read(reader)? {
122 0u8 => Ok(SpendableOutputDescriptor::StaticOutput {
123 outpoint: Readable::read(reader)?,
124 output: Readable::read(reader)?,
126 1u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WSH {
127 outpoint: Readable::read(reader)?,
128 key: Readable::read(reader)?,
129 witness_script: Readable::read(reader)?,
130 to_self_delay: Readable::read(reader)?,
131 output: Readable::read(reader)?,
133 2u8 => Ok(SpendableOutputDescriptor::DynamicOutputP2WPKH {
134 outpoint: Readable::read(reader)?,
135 key: Readable::read(reader)?,
136 output: Readable::read(reader)?,
138 _ => Err(DecodeError::InvalidValue),
143 /// A trait to describe an object which can get user secrets and key material.
144 pub trait KeysInterface: Send + Sync {
145 /// A type which implements ChannelKeys which will be returned by get_channel_keys.
146 type ChanKeySigner : ChannelKeys;
148 /// Get node secret key (aka node_id or network_key)
149 fn get_node_secret(&self) -> SecretKey;
150 /// Get destination redeemScript to encumber static protocol exit points.
151 fn get_destination_script(&self) -> Script;
152 /// Get shutdown_pubkey to use as PublicKey at channel closure
153 fn get_shutdown_pubkey(&self) -> PublicKey;
154 /// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you
155 /// restarted with some stale data!
156 fn get_channel_keys(&self, inbound: bool, channel_value_satoshis: u64) -> Self::ChanKeySigner;
157 /// Get a secret and PRNG seed for construting an onion packet
158 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]);
159 /// Get a unique temporary channel id. Channels will be referred to by this until the funding
160 /// transaction is created, at which point they will use the outpoint in the funding
162 fn get_channel_id(&self) -> [u8; 32];
165 /// Set of lightning keys needed to operate a channel as described in BOLT 3.
167 /// Signing services could be implemented on a hardware wallet. In this case,
168 /// the current ChannelKeys would be a front-end on top of a communication
169 /// channel connected to your secure device and lightning key material wouldn't
170 /// reside on a hot server. Nevertheless, a this deployment would still need
171 /// to trust the ChannelManager to avoid loss of funds as this latest component
172 /// could ask to sign commitment transaction with HTLCs paying to attacker pubkeys.
174 /// A more secure iteration would be to use hashlock (or payment points) to pair
175 /// invoice/incoming HTLCs with outgoing HTLCs to implement a no-trust-ChannelManager
176 /// at the price of more state and computation on the hardware wallet side. In the future,
177 /// we are looking forward to design such interface.
179 /// In any case, ChannelMonitor or fallback watchtowers are always going to be trusted
180 /// to act, as liveness and breach reply correctness are always going to be hard requirements
181 /// of LN security model, orthogonal of key management issues.
183 /// If you're implementing a custom signer, you almost certainly want to implement
184 /// Readable/Writable to serialize out a unique reference to this set of keys so
185 /// that you can serialize the full ChannelManager object.
187 // (TODO: We shouldn't require that, and should have an API to get them at deser time, due mostly
188 // to the possibility of reentrancy issues by calling the user's code during our deserialization
190 // TODO: We should remove Clone by instead requesting a new ChannelKeys copy when we create
191 // ChannelMonitors instead of expecting to clone the one out of the Channel into the monitors.
192 pub trait ChannelKeys : Send+Clone {
193 /// Gets the private key for the anchor tx
194 fn funding_key<'a>(&'a self) -> &'a SecretKey;
195 /// Gets the local secret key for blinded revocation pubkey
196 fn revocation_base_key<'a>(&'a self) -> &'a SecretKey;
197 /// Gets the local secret key used in to_remote output of remote commitment tx
198 /// (and also as part of obscured commitment number)
199 fn payment_base_key<'a>(&'a self) -> &'a SecretKey;
200 /// Gets the local secret key used in HTLC-Success/HTLC-Timeout txn and to_local output
201 fn delayed_payment_base_key<'a>(&'a self) -> &'a SecretKey;
202 /// Gets the local htlc secret key used in commitment tx htlc outputs
203 fn htlc_base_key<'a>(&'a self) -> &'a SecretKey;
204 /// Gets the commitment seed
205 fn commitment_seed<'a>(&'a self) -> &'a [u8; 32];
206 /// Gets the local channel public keys and basepoints
207 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys;
209 /// Create a signature for a remote commitment transaction and associated HTLC transactions.
211 /// Note that if signing fails or is rejected, the channel will be force-closed.
213 // TODO: Document the things someone using this interface should enforce before signing.
214 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
215 // making the callee generate it via some util function we expose)!
216 fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()>;
218 /// Create a signature for a local commitment transaction. This will only ever be called with
219 /// the same local_commitment_tx (or a copy thereof), though there are currently no guarantees
220 /// that it will not be called multiple times.
222 // TODO: Document the things someone using this interface should enforce before signing.
223 // TODO: Add more input vars to enable better checking (preferably removing commitment_tx and
224 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
226 /// Same as sign_local_commitment, but exists only for tests to get access to local commitment
227 /// transactions which will be broadcasted later, after the channel has moved on to a newer
228 /// state. Thus, needs its own method as sign_local_commitment may enforce that we only ever
231 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
233 /// Create a signature for each HTLC transaction spending a local commitment transaction.
235 /// Unlike sign_local_commitment, this may be called multiple times with *different*
236 /// local_commitment_tx values. While this will never be called with a revoked
237 /// local_commitment_tx, it is possible that it is called with the second-latest
238 /// local_commitment_tx (only if we haven't yet revoked it) if some watchtower/secondary
239 /// ChannelMonitor decided to broadcast before it had been updated to the latest.
241 /// Either an Err should be returned, or a Vec with one entry for each HTLC which exists in
242 /// local_commitment_tx. For those HTLCs which have transaction_output_index set to None
243 /// (implying they were considered dust at the time the commitment transaction was negotiated),
244 /// a corresponding None should be included in the return value. All other positions in the
245 /// return value must contain a signature.
246 fn sign_local_commitment_htlc_transactions<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, local_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()>;
248 /// Create a signature for a (proposed) closing transaction.
250 /// Note that, due to rounding, there may be one "missing" satoshi, and either party may have
251 /// chosen to forgo their output as dust.
252 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
254 /// Signs a channel announcement message with our funding key, proving it comes from one
255 /// of the channel participants.
257 /// Note that if this fails or is rejected, the channel will not be publicly announced and
258 /// our counterparty may (though likely will not) close the channel on us for violating the
260 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()>;
262 /// Set the remote channel basepoints. This is done immediately on incoming channels
263 /// and as soon as the channel is accepted on outgoing channels.
265 /// Will be called before any signatures are applied.
266 fn set_remote_channel_pubkeys(&mut self, channel_points: &ChannelPublicKeys);
270 /// A simple implementation of ChannelKeys that just keeps the private keys in memory.
271 pub struct InMemoryChannelKeys {
272 /// Private key of anchor tx
273 funding_key: SecretKey,
274 /// Local secret key for blinded revocation pubkey
275 revocation_base_key: SecretKey,
276 /// Local secret key used in commitment tx htlc outputs
277 payment_base_key: SecretKey,
278 /// Local secret key used in HTLC tx
279 delayed_payment_base_key: SecretKey,
280 /// Local htlc secret key used in commitment tx htlc outputs
281 htlc_base_key: SecretKey,
283 commitment_seed: [u8; 32],
284 /// Local public keys and basepoints
285 pub(crate) local_channel_pubkeys: ChannelPublicKeys,
286 /// Remote public keys and base points
287 pub(crate) remote_channel_pubkeys: Option<ChannelPublicKeys>,
288 /// The total value of this channel
289 channel_value_satoshis: u64,
292 impl InMemoryChannelKeys {
293 /// Create a new InMemoryChannelKeys
294 pub fn new<C: Signing>(
295 secp_ctx: &Secp256k1<C>,
296 funding_key: SecretKey,
297 revocation_base_key: SecretKey,
298 payment_base_key: SecretKey,
299 delayed_payment_base_key: SecretKey,
300 htlc_base_key: SecretKey,
301 commitment_seed: [u8; 32],
302 channel_value_satoshis: u64) -> InMemoryChannelKeys {
303 let local_channel_pubkeys =
304 InMemoryChannelKeys::make_local_keys(secp_ctx, &funding_key, &revocation_base_key,
305 &payment_base_key, &delayed_payment_base_key,
307 InMemoryChannelKeys {
311 delayed_payment_base_key,
314 channel_value_satoshis,
315 local_channel_pubkeys,
316 remote_channel_pubkeys: None,
320 fn make_local_keys<C: Signing>(secp_ctx: &Secp256k1<C>,
321 funding_key: &SecretKey,
322 revocation_base_key: &SecretKey,
323 payment_base_key: &SecretKey,
324 delayed_payment_base_key: &SecretKey,
325 htlc_base_key: &SecretKey) -> ChannelPublicKeys {
326 let from_secret = |s: &SecretKey| PublicKey::from_secret_key(secp_ctx, s);
328 funding_pubkey: from_secret(&funding_key),
329 revocation_basepoint: from_secret(&revocation_base_key),
330 payment_basepoint: from_secret(&payment_base_key),
331 delayed_payment_basepoint: from_secret(&delayed_payment_base_key),
332 htlc_basepoint: from_secret(&htlc_base_key),
337 impl ChannelKeys for InMemoryChannelKeys {
338 fn funding_key(&self) -> &SecretKey { &self.funding_key }
339 fn revocation_base_key(&self) -> &SecretKey { &self.revocation_base_key }
340 fn payment_base_key(&self) -> &SecretKey { &self.payment_base_key }
341 fn delayed_payment_base_key(&self) -> &SecretKey { &self.delayed_payment_base_key }
342 fn htlc_base_key(&self) -> &SecretKey { &self.htlc_base_key }
343 fn commitment_seed(&self) -> &[u8; 32] { &self.commitment_seed }
344 fn pubkeys<'a>(&'a self) -> &'a ChannelPublicKeys { &self.local_channel_pubkeys }
346 fn sign_remote_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, feerate_per_kw: u64, commitment_tx: &Transaction, keys: &TxCreationKeys, htlcs: &[&HTLCOutputInCommitment], to_self_delay: u16, secp_ctx: &Secp256k1<T>) -> Result<(Signature, Vec<Signature>), ()> {
347 if commitment_tx.input.len() != 1 { return Err(()); }
349 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
350 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
351 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
353 let commitment_sighash = hash_to_message!(&bip143::SighashComponents::new(&commitment_tx).sighash_all(&commitment_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
354 let commitment_sig = secp_ctx.sign(&commitment_sighash, &self.funding_key);
356 let commitment_txid = commitment_tx.txid();
358 let mut htlc_sigs = Vec::with_capacity(htlcs.len());
359 for ref htlc in htlcs {
360 if let Some(_) = htlc.transaction_output_index {
361 let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, feerate_per_kw, to_self_delay, htlc, &keys.a_delayed_payment_key, &keys.revocation_key);
362 let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys);
363 let htlc_sighash = hash_to_message!(&bip143::SighashComponents::new(&htlc_tx).sighash_all(&htlc_tx.input[0], &htlc_redeemscript, htlc.amount_msat / 1000)[..]);
364 let our_htlc_key = match chan_utils::derive_private_key(&secp_ctx, &keys.per_commitment_point, &self.htlc_base_key) {
366 Err(_) => return Err(()),
368 htlc_sigs.push(secp_ctx.sign(&htlc_sighash, &our_htlc_key));
372 Ok((commitment_sig, htlc_sigs))
375 fn sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
376 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
377 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
378 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
380 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
384 fn unsafe_sign_local_commitment<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
385 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
386 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
387 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
389 Ok(local_commitment_tx.get_local_sig(&self.funding_key, &channel_funding_redeemscript, self.channel_value_satoshis, secp_ctx))
392 fn sign_local_commitment_htlc_transactions<T: secp256k1::Signing + secp256k1::Verification>(&self, local_commitment_tx: &LocalCommitmentTransaction, local_csv: u16, secp_ctx: &Secp256k1<T>) -> Result<Vec<Option<Signature>>, ()> {
393 local_commitment_tx.get_htlc_sigs(&self.htlc_base_key, local_csv, secp_ctx)
396 fn sign_closing_transaction<T: secp256k1::Signing>(&self, closing_tx: &Transaction, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
397 if closing_tx.input.len() != 1 { return Err(()); }
398 if closing_tx.input[0].witness.len() != 0 { return Err(()); }
399 if closing_tx.output.len() > 2 { return Err(()); }
401 let remote_channel_pubkeys = self.remote_channel_pubkeys.as_ref().expect("must set remote channel pubkeys before signing");
402 let funding_pubkey = PublicKey::from_secret_key(secp_ctx, &self.funding_key);
403 let channel_funding_redeemscript = make_funding_redeemscript(&funding_pubkey, &remote_channel_pubkeys.funding_pubkey);
405 let sighash = hash_to_message!(&bip143::SighashComponents::new(closing_tx)
406 .sighash_all(&closing_tx.input[0], &channel_funding_redeemscript, self.channel_value_satoshis)[..]);
407 Ok(secp_ctx.sign(&sighash, &self.funding_key))
410 fn sign_channel_announcement<T: secp256k1::Signing>(&self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<Signature, ()> {
411 let msghash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
412 Ok(secp_ctx.sign(&msghash, &self.funding_key))
415 fn set_remote_channel_pubkeys(&mut self, channel_pubkeys: &ChannelPublicKeys) {
416 assert!(self.remote_channel_pubkeys.is_none(), "Already set remote channel pubkeys");
417 self.remote_channel_pubkeys = Some(channel_pubkeys.clone());
421 impl Writeable for InMemoryChannelKeys {
422 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
423 self.funding_key.write(writer)?;
424 self.revocation_base_key.write(writer)?;
425 self.payment_base_key.write(writer)?;
426 self.delayed_payment_base_key.write(writer)?;
427 self.htlc_base_key.write(writer)?;
428 self.commitment_seed.write(writer)?;
429 self.remote_channel_pubkeys.write(writer)?;
430 self.channel_value_satoshis.write(writer)?;
436 impl Readable for InMemoryChannelKeys {
437 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
438 let funding_key = Readable::read(reader)?;
439 let revocation_base_key = Readable::read(reader)?;
440 let payment_base_key = Readable::read(reader)?;
441 let delayed_payment_base_key = Readable::read(reader)?;
442 let htlc_base_key = Readable::read(reader)?;
443 let commitment_seed = Readable::read(reader)?;
444 let remote_channel_pubkeys = Readable::read(reader)?;
445 let channel_value_satoshis = Readable::read(reader)?;
446 let secp_ctx = Secp256k1::signing_only();
447 let local_channel_pubkeys =
448 InMemoryChannelKeys::make_local_keys(&secp_ctx, &funding_key, &revocation_base_key,
449 &payment_base_key, &delayed_payment_base_key,
452 Ok(InMemoryChannelKeys {
456 delayed_payment_base_key,
459 channel_value_satoshis,
460 local_channel_pubkeys,
461 remote_channel_pubkeys
466 /// Simple KeysInterface implementor that takes a 32-byte seed for use as a BIP 32 extended key
467 /// and derives keys from that.
469 /// Your node_id is seed/0'
470 /// ChannelMonitor closes may use seed/1'
471 /// Cooperative closes may use seed/2'
472 /// The two close keys may be needed to claim on-chain funds!
473 pub struct KeysManager {
474 secp_ctx: Secp256k1<secp256k1::SignOnly>,
475 node_secret: SecretKey,
476 destination_script: Script,
477 shutdown_pubkey: PublicKey,
478 channel_master_key: ExtendedPrivKey,
479 channel_child_index: AtomicUsize,
480 session_master_key: ExtendedPrivKey,
481 session_child_index: AtomicUsize,
482 channel_id_master_key: ExtendedPrivKey,
483 channel_id_child_index: AtomicUsize,
485 unique_start: Sha256State,
490 /// Constructs a KeysManager from a 32-byte seed. If the seed is in some way biased (eg your
491 /// RNG is busted) this may panic (but more importantly, you will possibly lose funds).
492 /// starting_time isn't strictly required to actually be a time, but it must absolutely,
493 /// without a doubt, be unique to this instance. ie if you start multiple times with the same
494 /// seed, starting_time must be unique to each run. Thus, the easiest way to achieve this is to
495 /// simply use the current time (with very high precision).
497 /// The seed MUST be backed up safely prior to use so that the keys can be re-created, however,
498 /// obviously, starting_time should be unique every time you reload the library - it is only
499 /// used to generate new ephemeral key data (which will be stored by the individual channel if
502 /// Note that the seed is required to recover certain on-chain funds independent of
503 /// ChannelMonitor data, though a current copy of ChannelMonitor data is also required for any
504 /// channel, and some on-chain during-closing funds.
506 /// Note that until the 0.1 release there is no guarantee of backward compatibility between
507 /// versions. Once the library is more fully supported, the docs will be updated to include a
508 /// detailed description of the guarantee.
509 pub fn new(seed: &[u8; 32], network: Network, logger: Arc<Logger>, starting_time_secs: u64, starting_time_nanos: u32) -> KeysManager {
510 let secp_ctx = Secp256k1::signing_only();
511 match ExtendedPrivKey::new_master(network.clone(), seed) {
513 let node_secret = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(0).unwrap()).expect("Your RNG is busted").private_key.key;
514 let destination_script = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(1).unwrap()) {
515 Ok(destination_key) => {
516 let pubkey_hash160 = Hash160::hash(&ExtendedPubKey::from_private(&secp_ctx, &destination_key).public_key.key.serialize()[..]);
517 Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0)
518 .push_slice(&pubkey_hash160.into_inner())
521 Err(_) => panic!("Your RNG is busted"),
523 let shutdown_pubkey = match master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(2).unwrap()) {
524 Ok(shutdown_key) => ExtendedPubKey::from_private(&secp_ctx, &shutdown_key).public_key.key,
525 Err(_) => panic!("Your RNG is busted"),
527 let channel_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(3).unwrap()).expect("Your RNG is busted");
528 let session_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(4).unwrap()).expect("Your RNG is busted");
529 let channel_id_master_key = master_key.ckd_priv(&secp_ctx, ChildNumber::from_hardened_idx(5).unwrap()).expect("Your RNG is busted");
531 let mut unique_start = Sha256::engine();
532 unique_start.input(&byte_utils::be64_to_array(starting_time_secs));
533 unique_start.input(&byte_utils::be32_to_array(starting_time_nanos));
534 unique_start.input(seed);
542 channel_child_index: AtomicUsize::new(0),
544 session_child_index: AtomicUsize::new(0),
545 channel_id_master_key,
546 channel_id_child_index: AtomicUsize::new(0),
552 Err(_) => panic!("Your rng is busted"),
557 impl KeysInterface for KeysManager {
558 type ChanKeySigner = InMemoryChannelKeys;
560 fn get_node_secret(&self) -> SecretKey {
561 self.node_secret.clone()
564 fn get_destination_script(&self) -> Script {
565 self.destination_script.clone()
568 fn get_shutdown_pubkey(&self) -> PublicKey {
569 self.shutdown_pubkey.clone()
572 fn get_channel_keys(&self, _inbound: bool, channel_value_satoshis: u64) -> InMemoryChannelKeys {
573 // We only seriously intend to rely on the channel_master_key for true secure
574 // entropy, everything else just ensures uniqueness. We rely on the unique_start (ie
575 // starting_time provided in the constructor) to be unique.
576 let mut sha = self.unique_start.clone();
578 let child_ix = self.channel_child_index.fetch_add(1, Ordering::AcqRel);
579 let child_privkey = self.channel_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted");
580 sha.input(&child_privkey.private_key.key[..]);
582 let seed = Sha256::from_engine(sha).into_inner();
584 let commitment_seed = {
585 let mut sha = Sha256::engine();
587 sha.input(&b"commitment seed"[..]);
588 Sha256::from_engine(sha).into_inner()
590 macro_rules! key_step {
591 ($info: expr, $prev_key: expr) => {{
592 let mut sha = Sha256::engine();
594 sha.input(&$prev_key[..]);
595 sha.input(&$info[..]);
596 SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("SHA-256 is busted")
599 let funding_key = key_step!(b"funding key", commitment_seed);
600 let revocation_base_key = key_step!(b"revocation base key", funding_key);
601 let payment_base_key = key_step!(b"payment base key", revocation_base_key);
602 let delayed_payment_base_key = key_step!(b"delayed payment base key", payment_base_key);
603 let htlc_base_key = key_step!(b"HTLC base key", delayed_payment_base_key);
605 InMemoryChannelKeys::new(
610 delayed_payment_base_key,
613 channel_value_satoshis
617 fn get_onion_rand(&self) -> (SecretKey, [u8; 32]) {
618 let mut sha = self.unique_start.clone();
620 let child_ix = self.session_child_index.fetch_add(1, Ordering::AcqRel);
621 let child_privkey = self.session_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted");
622 sha.input(&child_privkey.private_key.key[..]);
624 let mut rng_seed = sha.clone();
625 // Not exactly the most ideal construction, but the second value will get fed into
626 // ChaCha so it is another step harder to break.
627 rng_seed.input(b"RNG Seed Salt");
628 sha.input(b"Session Key Salt");
629 (SecretKey::from_slice(&Sha256::from_engine(sha).into_inner()).expect("Your RNG is busted"),
630 Sha256::from_engine(rng_seed).into_inner())
633 fn get_channel_id(&self) -> [u8; 32] {
634 let mut sha = self.unique_start.clone();
636 let child_ix = self.channel_id_child_index.fetch_add(1, Ordering::AcqRel);
637 let child_privkey = self.channel_id_master_key.ckd_priv(&self.secp_ctx, ChildNumber::from_hardened_idx(child_ix as u32).expect("key space exhausted")).expect("Your RNG is busted");
638 sha.input(&child_privkey.private_key.key[..]);
640 Sha256::from_engine(sha).into_inner()